Low-power high-frequency directional tunable ac magnetic field

Abstract

Apparatus for near-field wireless energy transfer. A first layer provides or comprises a piezoelectric phase or a material with or adapted for electromechanical coupling; and a second layer provides or comprises a magnetostrictive phase or a material with or adapted for a magnetomechanical coupling. The second layer is mechanically and/or chemically coupled to the first layer to provide a composite structure.

What is claimed is: 
     
         1 . A system for near-field wireless energy transfer, the apparatus comprising:
 a first multilayer composite structure comprising:
 at least one outer layer of a piezoelectric material providing or comprising a piezoelectric phase or a material with or adapted for electromechanical coupling; and 
 at least one inner layer of a magnetostrictive material providing or comprising a magnetostrictive phase or a material with or adapted for a magnetomechanical coupling; 
 wherein said at least outer layer is joined, adherent to or bonded to at least one of said at least one inner layer; and 
 an electric field generator for applying an electric field to the piezoelectric phase to generate strain. 
   
     
     
         2 . The system of  claim 1 , further comprising:
 a second multilayer composite structure comprising:
 at least one outer layer of a piezoelectric material providing or comprising a piezoelectric phase or a material with or adapted for electromechanical coupling; and 
 at least one inner layer of a magnetostrictive material providing or comprising a magnetostrictive phase or a material with or adapted for a magnetomechanical coupling; 
 wherein said at least outer layer is joined, adherent to or bonded to at least one of said at least one inner layer; 
   wherein the second multilayer composite structure is wirelessly coupled to the first multilayer composite for wireless energy transfer.   
     
     
         3 . The system of  claim 2 ,
 wherein the inner and outer layers of the first multilayer structure define concentric rings;   wherein the inner and outer layers of the second multilayer structure are arranged with respect to one another in a stacking sequence;   wherein the first multilayer structure surrounds the second multilayer structure; and   wherein the first, outer multilayer structure provides or comprises a transmitter and the second, inner multilayer structure provides or comprises a receiver;   wherein said transmitter and said receiver are not coupled to one another via conductive media.   
     
     
         4 . The system of  claim 2 ,
 wherein the inner and outer layers of the second multilayer structure define concentric rings;   wherein the inner and outer layers of the first multilayer structure are arranged with respect to one another in a stacking sequence;   wherein the second multilayer structure surrounds the first multilayer structure; and   wherein the first, inner multilayer structure provides or comprises a transmitter and the second, outer multilayer structure provides or comprises a receiver;   wherein said transmitter and said receiver are not coupled to one another via conductive media.   
     
     
         5 . The system of  claim 2 , wherein the piezoelectric materials are radially polarized. 
     
     
         6 . The system of  claim 2 , wherein the magnetostrictive material comprises a terbium, dysprosium, and/or an iron alloy. 
     
     
         7 . A method for providing near-field wireless energy transfer, the method comprising:
 providing a multiferroic composite structure comprising:
 a first layer being formed from a material comprising polarized piezoelectric material; 
 a second layer formed from a material comprising terbium, dysprosium, and iron alloy; and 
 a bonding, coupling or adhesive agent bonding, coupling or adhering said first and second layers; and 
 applying an electric or a magnetic field to the multiferroic composite structure. 
   
     
     
         8 . The method of  claim 7 , wherein said applying an electric or a magnetic field comprises applying a magnetic field to the composite structure to induce a change in polarization through strain transduction at an interface between the first and second layers. 
     
     
         9 . The method of  claim 7 , wherein said applying an electric or a magnetic field comprises applying an alternating current (AC) electric field to the composite structure to cause the composite multilayer structure to emanate an AC magnetic field via converse magnetoelectric coupling. 
     
     
         10 . The method of  claim 7 , wherein said applying an electric or a magnetic field comprises:
 applying an AC voltage to said second layer to cause said second layer to generate an electric field to said first layer;   wherein said electric field causes said first layer to vibrate;   wherein the vibration of said first layer applies a strain onto said second layer to cause said second layer to create the AC magnetic field.   
     
     
         11 . The method of  claim 10 ,
 wherein said first and second layers are respectively arranged in a concentric ring structure; and   wherein said applying an AC voltage causes said second layer to radially vibrate.   
     
     
         12 . The method of  claim 9 , further comprising:
 throttling the applied voltage to linearly control a magnitude of the AC magnetic field generated by the composite structure.   
     
     
         13 . The method of  claim 7 , further comprising:
 polarizing the first layer in a polarization direction.